Portable transmitter



FIG. 1 is a rear, bottom, and right side perspective view of a portable transmitter, showing our new design;

FIG. 2 is a rear, top and left side perspective view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a left side elevational view thereof; and

FIG. 6 is a top plan view thereof. 

The ornamental design for a portable transmitter, substantially as shown and described. 